In this paper, we compare the Marangoni effect and the effect of the Prandtl number variation on features of the liquid film rupture under the action of a thermal load and show a principal difference between these two effects. Results of computational analysis allow us to make the following conclusions. When affecting on the free surface of the plane liquid film by thermal beam, in order to obtain the initial holes of the same size in films with various thermal physical properties, one should apply a thermal load of a certain well-defined type, more specifically, concentrated thermal load, which provides the predetermined temperature at least on one of the film boundaries. In this case the size of the holes will depend only on the width of a thermal beam applied to the film free surface. Paper presents the solutions of the model problems. (C) 2014 Elsevier Ltd. All rights reserved.